The present invention relates to the field of laminated plastic display devices and includes those used in marketing goods and services.
In U.S. Pat. Nos. 5,042,843 and 5,090,732 incorporated by reference herein and issued to Roger Kuhns et al., and assigned to Avant Inc. of West Concord, Mass., presentation folders are disclosed for storing and displaying sheets of sales material in pouches formed in the folders and which folders may also be rapidly customized by laminating customized insert sheets to the folders by the application of heat and pressure thereto, thereby to result in the production of a highly attracive product. The insert sheets are like the front and back slip-cover of a book and enhance the advertising value of the presentation folder. The graphics and printed matter on the insert sheets may be easily and rapidly produced by a PC desk top publishing program.
It is also known in the art to produce presentation booklets having edge portions of a stack of sheets of promotional material bonded by a heat activatable adhesive material to a spine portion. The result is a sales presentation booklet. This process is well known in the art as perfect binding. Surprisingly, and to the best of our knowledge, no one has marketed a dual-function product that includes both the customized presentation folder having pouches for holding loose sheets as described in the aforesaid patents, and sheets which are bound within the folder by means of perfect binding through the use of a heat activatable adhesive. It is thus an object of the present invention to easily and rapidly produce such a dual function product in an economical manner.
The lamination by heat and pressure of the customized insert sheets between the folder sheets and the heat activatable plastic cover sheets of the presentation folders in the aforesaid patents, is carried out by feeding the folder between rollers of what is known in the trade as a pouch laminator. The plastic cover sheets, covering the customized paper insert sheets, are laminated to the paper folder sheet by the application of heat and pressure as the folder is passed through the pouch laminator. A first pair of entrance rollers conveys the "sandwich" to be laminated between hot platens which melt the heat activatable adhesive, which is commonly polyethylene. The adhesive layer is on the inside surface of the plastic cover sheet facing the paper folder sheet, and the melting of the adhesive laminates the cover sheet to the folder sheet while encapsulating the customized insert sheet between them. A second pair of exit rollers completes the lamination by the application of pressure to the now molten heat activatable adhesive.
During the development of the aforesaid dual function product, we encountered problems in passing the dual function product through the pouch laminator as just described. The presentation folder of the aforesaid patents was modified by forming a pair of closely spaced vertically oriented folds for dividing the folder into a pair of major face portions and for defining a perfect binding adhesive strip receiving area which will be later used to receive the adhesive strip which binds edges of a stack of sheets to the strip by means of a heat activatable adhesive.
These modified presentation folders had the plastic cover sheets affixed to top edge portions of the folders via a heat seal and the customized insert sheets were abutted against the heat seals at the top edge portions as shown in the aforesaid patents. The right half major folder portion was folded over the left hand major folder portion to enfold the plastic cover sheet. The resulting "sandwich" was then passed through the laminator whereby the top heat seal portion was first passed through the entrance roller pair. In other words, the sides of the plastic cover sheets were parallel to the direction of feed of the "sandwich" through the laminator. This procedure, was carried out essentially in accordance with the procedures and folders of the aforesaid patents except for the addition of the second vertically positioned fold which, along with the first fold, defined the perfect binding adhesive strip receiving area or channel for later receiving a strip of heat activatable adhesive to carry out the perfect binding of the edges of the sheets to the central portion of the presentation folder. This simple modification of the prior presentation folders of the patents produced substantial aesthetically unacceptable wrinkling of the plastic cover sheets after being passed through the laminator.
We believe that this unacceptable wrinkling is caused by the fact that the thickness of the side of the folder where the adhesive strip receiving channel is present is less than the thickness of the opposite side portion of the folder. This is because edge portions of the plastic cover sheet and edge portions of the plastic backing sheet extend to the edges of the folder. 0n the other hand, the side of the folder comprising the perfect binding strip receiving channel is not covered by plastic since the edge of the plastic cover sheet does not cover the strip receiving channel area.